1. Technical Field
The present disclosure relates to data warehousing and more specifically to generation of star schemas from snowflake schemas containing a large number of dimensions.
2. Related Art
Star schema (also known as a star join schema) refers to a type of schema in which tables are designed with redundancy of data. Star schemas organize data in terms of fact tables and dimension tables, with fact tables containing detailed data of interest (e.g., aggregated information or detailed counts, etc.,) and the dimension tables containing attributes (or fields) used to constrain and group data when performing data warehousing queries. Each fact table may be viewed as having multiple dimensions, with each dimension represented by a corresponding dimension table.
Due to such organization as fact tables and dimension tables, later retrieval of related data is simplified, thereby making star schemas suitable for environments, such as data warehousing, requiring analysis and/or reporting of data (which is unlikely to change).
Snowflake schema refers to a type of normalized star schema, where a dimension of a fact table is represented by multiple dimension tables. Such multiple dimension tables are organized in normalized form (without redundancy). Such organization is often chosen to avoid expending fields/space for data that is not of interest (or otherwise need not be stored) in the fact tables.
There is often a need to generate star schemas from snowflake schemas, particularly when there are a large number of dimensions and/or dimension tables.
In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the corresponding reference number.